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  <title>获取字符串长度</title>
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  <div id="layout-content"><div id="function.strlen" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">strlen</h1>
  <p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">strlen</span> &mdash; <span class="dc-title">获取字符串长度</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-function.strlen-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>strlen</strong></span>
    ( <span class="methodparam"><span class="type">string</span> <code class="parameter">$string</code></span>
   ) : <span class="type">int</span></div>

  <p class="para rdfs-comment">
   返回给定的字符串 <code class="parameter">string</code> 的长度。
  </p>
 </div>


 <div class="refsect1 parameters" id="refsect1-function.strlen-parameters">
  <h3 class="title">参数</h3>
  <p class="para">
   <dl>

    
     <dt>
<code class="parameter">string</code></dt>

     <dd>

      <p class="para">
       需要计算长度的<span class="type"><span class="type 字符串">字符串</span></span>。
      </p>
     </dd>

    
   </dl>

  </p>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-function.strlen-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="para">
   成功则返回字符串 <code class="parameter">string</code> 的长度；如果 <code class="parameter">string</code> 为空，则返回 0。
  </p>
 </div>


 <div class="refsect1 changelog" id="refsect1-function.strlen-changelog">
  <h3 class="title">更新日志</h3>
  <table class="doctable informaltable">
   
    <thead>
     <tr>
      <th>版本</th>
      <th>说明</th>
     </tr>

    </thead>

    <tbody class="tbody">
     <tr>
      <td>5.3.0</td>
      <td>
       Prior versions treated arrays as the string <em>Array</em>, thus returning
       a string length of <em>5</em> and emitting an <strong><code>E_NOTICE</code></strong> level error.
      </td>
     </tr>

    </tbody>
   
  </table>

 </div>


 <div class="refsect1 examples" id="refsect1-function.strlen-examples">
  <h3 class="title">范例</h3>
  <p class="para">
   <div class="example" id="example-5972">
    <p><strong>Example #1 <span class="function"><strong>strlen()</strong></span> 范例</strong></p>
    <div class="example-contents">
<div class="phpcode"><pre><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br />$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'abcdef'</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;6<br /><br /></span><span style="color: #0000BB">$str&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'&nbsp;ab&nbsp;cd&nbsp;'</span><span style="color: #007700">;<br />echo&nbsp;</span><span style="color: #0000BB">strlen</span><span style="color: #007700">(</span><span style="color: #0000BB">$str</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;7<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</pre></div>
    </div>

   </div>
  </p>
 </div>


 <div class="refsect1 notes" id="refsect1-function.strlen-notes">
  <h3 class="title">注释</h3>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    <span class="function"><strong>strlen()</strong></span> returns the number of bytes rather than the number 
    of characters in a string.
   </p>
  </p></blockquote>
  <blockquote class="note"><p><strong class="note">Note</strong>: 
   <p class="para">
    <span class="function"><strong>strlen()</strong></span> returns <strong><code>NULL</code></strong> when executed on arrays, and
    an <strong><code>E_WARNING</code></strong> level error is emitted.
   </p>
  </p></blockquote>
 </div>


 <div class="refsect1 seealso" id="refsect1-function.strlen-seealso">
  <h3 class="title">参见</h3>
  <p class="para">
   <ul class="simplelist">
    <li class="member"><span class="function"><a href="count.html" class="function" rel="rdfs-seeAlso">count()</a> - 计算数组中的单元数目，或对象中的属性个数</span></li>
    <li class="member"><span class="function"><a href="mb_strlen.html" class="function" rel="rdfs-seeAlso">mb_strlen()</a> - 获取字符串的长度</span></li>
   </ul>
  </p>
 </div>


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